Im trying to print an image in CS4. I have the retocuhed layered image, and it looks exactly the way I like it. But for some reason when I flatten it it looks lighter and brings up some banding artifacts. If I print this flattened version it prints lighter and with the artifacts. However if I send to print the layered version it prints perfectly fine. Problem comes because I have to send the flattened version to client along with the match print. So the print will be fine, but the flattened version will be lighter and with the artifacts.

If you have image layers paired with a clipping masked adjustment layers, try merging those layers with their respective adjustment layers first, before flattening the whole image. I had an issue with CS3 in that regard, that fixed it for me but I don't understand why.